ES2655473T3 - Process for the production of olefinic compounds and a hydrocarbon fuel or a fraction thereof - Google Patents

Abstract

Process for producing olefinic compounds and a hydrocarbon fuel or a fraction thereof, which comprises: (a) metastasizing a mixture of glycerides having at least one unsaturated hydrocarbon chain, possibly mixed with free fatty acids, with at least one C2-C6 monoolefin, in the presence of a metathesis catalyst, in order to obtain a mixture of glycerides having at least one unsaturated hydrocarbon chain with a length less than the initial one, and a mixture of C6-C18 olefins; (b) separating the C6-C18 olefin mixture from the glyceride mixture obtained in step (a); (c) subjecting the glyceride mixture obtained in step (b) to a transesterification reaction with an alcohol selected from methanol, ethanol or mixtures thereof, in order to obtain a mixture of methyl and / or ethyl esters and glycerol; (c ') separate the glycerol from the mixture of methyl and / or ethyl esters, and then (c ") separate the methyl and / or ethyl esters having an unsaturated hydrocarbon chain from the methyl and / or ethyl esters that they have a saturated hydrocarbon chain, (d) subject the methyl and / or ethyl esters having a saturated hydrocarbon chain obtained in step (c ") to a catalytic hydroxy oxygenation process and then catalytic hydroisomerization, in order to obtain the hydrocarbon fuel or a fraction thereof.

Description

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DESCRIPTION

Process for the production of olefinic compounds and a hydrocarbon fuel or a fraction thereof

The present invention relates to a process for the production of olefinic compounds and a hydrocarbon fuel or a fraction thereof, which comprises subjecting a mixture of glycerides having at least one unsaturated hydrocarbon chain to metathesis reaction and, after separating the mixture. olefinic obtained, perform a hydrodeoxygenation process and then hydroisomerization, in order to obtain the hydrocarbon fuel or a fraction thereof.

This process advantageously allows both olefinic compounds to be obtained, which can be used, for example, as intermediate products for the production of detergents, additives, lubricants and / or plastic materials or components that can be used in the field of oil exploration and production. , and also a hydrocarbon fuel, or fraction thereof, preferably selected from diesel, naphtha, aviation fuel or mixtures thereof.

Due to a decrease in fossil fuel reserves and the negative impact on the environment produced by anthropogenic emissions of carbon dioxide (CO2), technologies aimed at the production of fuels from biomass (called biofuels), which allow the time the complete transition to renewable energy sources, are increasingly important.

Among the new sustainable energy sources, biomass can contribute significantly to achieving these goals. Biomass are biodegradable plant or animal substances that derive from agriculture, forestry and all related industries, which include fishing, aquaculture and waste and wastes that come from them.

At the same time, the need to free oneself from fossil sources only and from the legislative obligations imposed on anthropogenic emissions is also felt in the production of chemical products, essential for daily life.

Therefore, the use of renewable sources such as biomass, which are economical and environmentally sustainable, may offer an alternative to the use of fossil sources for the production of useful chemicals in daily life (biochemicals, which are refers to its production from renewable sources).

Therefore, the development of the so-called "green chemistry" is underway, which implies a restructuring of the production chains through the use of renewable sources that derive from natural biomass and transformation technologies with low environmental emissions, which lead to creation of the so-called "biorefineries".

The process of the present invention can be advantageously carried out in a biorefinery, integrating the production of biofuels with the production of intermediate products useful for the production of detergents, additives, lubricants and / or plastic materials or components that can be used in the field of the exploration and production of petroleum (biochemicals), starting from the same renewable raw material, that is, a mixture of glycerides, preferably of vegetable or animal origin or of a microbial origin.

In the present invention, the integrated production of biofuels and biochemicals is obtained by a process comprising a metathesis reaction followed by the conversion of a part of the metathesis products.

Currently, the production of biofuels from renewable sources, such as natural oils, is carried out essentially through two main procedures:

I. transesterification, mainly with methanol, with the production of FAME (fatty acid methyl esters), normally called biodiesel; or

II. by catalytic procedures such as the so-called "hydrotreatment", with the production of paraffinic cuts, mainly diesel, but also gasoline, in varying proportions according to the procedures used.

In the first case, a biofuel is obtained, which, however, has several problems (for example, unsatisfactory yields at low temperature, in relation to instability in storage and distribution, etc.).

In the latter case, the starting oils are converted to hydrocarbon cuts with high properties, for example, complete miscibility with refinery cuts from fossil sources, high characteristics for engines such as cold properties and high cetane index, etc. Among the numerous hydrotreatment technologies available, the ENI / UOP Ecofining ™ procedure can be mentioned, as described, for example, in patent applications WO2008 / 058664, EP1728844, WO2009 / 039347, WO2009 / 039335, WO2009039333, WO2009 / 158268 and in US patent US7915460, all on behalf of ENI SpA and UOP 11c. He

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The main product of Ecofining's technology is the so-called green diesel and can be obtained with yields of up to 88% with respect to the starting oil or renewable source. The Ecofining process, based on natural oil, typically leads to the formation (by weight) of 4-5% propane, 1-8% naphtha cut, 75-85% diesel cut with approximately 1.5- 3.8% hydrogen consumption with respect to 100 of the starting biomass.

The hydrotreatment process, in particular called Ecofining, is a two-stage procedure: the first stage consists of a hydrogenation / deoxygenation reaction (hydrodeoxygenation) that eliminates all heteroatoms in the molecules, while the second stage is a hydroisomerization stage / cracking that allows to produce a diesel cut, which has the desired characteristics. In the first stage, the catalytic system carries out not only a deoxygenation of the raw material (reduction of esters to hydrocarbons), but also hydrogenates all possible double bonds present in fatty acids, whose esters form the starting oil . Therefore, the more unsaturated the starting mixture of fatty acids, the greater the specific hydrogen consumption of the catalytic hydrotreatment process.

Therefore, the possible feed streams for catalytic hydrotreatment processes composed of fully saturated oils represent particularly valuable feeds for said processes and in particular for the Ecofining process. Natural oils that can be obtained from crops, for example, are in fact a mixture of fatty acids in which the amount of unsaturated acids is not negligible.

More specifically, it would be desirable for these processes to have a feed stream obtained by selective transformation only of the unsaturated components present in the renewable source, where the initially present saturated components have been left unchanged.

US2010 / 0160506 describes a process comprising subjecting a mixture of glycerides and ethylene to metathesis followed by hydroisomerization.

Therefore, an object of the present invention relates to a process for the production of olefinic compounds and a hydrocarbon fuel or a fraction thereof, as defined in claim 1.

In particular, the hydrocarbon fuel or fraction thereof, produced with the process of the invention, is selected from: diesel, naphtha, aviation fuel, or mixtures thereof.

The mixture of C6-C18 olefins obtained from step (b) and / or the methyl and / or ethyl esters having an unsaturated hydrocarbon chain obtained from step (c ") are preferably intermediates that can be used for production. renewable (where "renewable production" refers to production from renewable sources, alternatives to fossil sources) of detergents, additives, lubricants and / or plastic materials or components, which can be used in the field of exploration and production of Petroleum.

The glycerides having at least one unsaturated hydrocarbon chain used in the mixture of step (a), are glycerides, preferably triglycerides, of plant or animal origin or of a microbial origin.

As indicated in US2009 / 0077865 paragraph [009], the term "renewable fats and oils" comprises glycerides and free fatty acids, wherein the glycerides are mainly triglycerides, but monoglycerides and triglycerides may also be present.

Said glycerides of vegetable or animal origin or of a microbial origin are preferably fatty acid glycerides having at least one mono or polyunsaturated C12-C24 hydrocarbon chain.

The glycerides used in the process of the invention are preferably selected from: vegetable oils, such as sunflower oil, rapeseed, canola, palm, soy, hemp, olive, flaxseed, mustard, peanut, castor, coconut and resin; oils and / or recycled fats from the food industry; lipids from algal cultures; animal oils or fats, such as: lard, cream of lard, tallow, dairy fats; or mixtures thereof.

The metathesis reaction carried out in step a) consists of a particular rearrangement of the substituents present in one or more double bonds. If the reaction is attributed to the double bonds of a single olefin, this is known as homo-metathesis. If, on the other hand, it is attributed to a mixture of two or more olefins, this is called co-metathesis. The latter has particular interest with respect to the present invention, and can be schematized as follows:

image 1

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In the case of oils, the most favorable option is its co-metathesis with a short olefin (C2-C6). Considering, for simplicity, only the co-metathesis of oleic acid esters (in general the most abundant among unsaturated compounds present in vegetable oils) with ethylene, the reaction gives a mixture of esters of 9-decen-1- oic acid 1-decene:

image2

In practice, due to the presence in the starting oil of esters of other unsaturated acids such as linoleic and linolenic acids, the products obtained are esters of 9-decen-1-oic acid and a mixture of C4-C10 a-olefins and 1,4-pentadiene, in addition to the saturated fraction to be fed to the hydrotreatment process. If the co-metathesis reaction were carried out with olefins other than ethylene, the distribution of the products obtained would be considerably different. With 1-butene, for example, there would be a mixture of esters of unsaturated C10-C13 acids, C4-C13, terminal and internal olefins, and olefins containing 5 to 9 carbon atoms.

The olefin used in the metathesis process of the present invention is a C2-C6 monoolefin, preferably C2-C4, selected from: ethylene, propene, 1-butene, but-2-ene, 2-methyl-propene, or mixtures of the same.

The molar ratio between the double bonds of the glyceride mixture having at least one unsaturated hydrocarbon chain and the double bonds of said at least one C2-C6 olefin used in step a), preferably is in the range of 1: 0, 1 to 1:20.

In addition, the preferred conditions for carrying out step (a) are a temperature in the range of 20 to 120 ° C, for a time in the range of 0.5 to 6 hours, preferably 20 to 80 ° C and of 0.5 to 3 hours

Step (a) is preferably carried out at a pressure in the range of 1 to 30 bar, and even more preferably the pressure is in the range of 1 to 15 bar.

The metathesis reaction is catalyzed by some transition metals such as, for example, ruthenium, molybdenum, osmium, chromium, rhenium and tungsten.

The metathesis catalyst of step (a) can be a carbine complex of a transition metal of group 8, in particular selected from: ruthenium, molybdenum, osmium, chromium, rhenium, tungsten.

The catalysis of stage a) can be homogeneous or heterogeneous.

The metathesis catalysts that can be used in the present invention are, for example, those described in the international patent application on behalf of Elevance Renewable Science Inc. publication number WO2008 / 046106 and in the international patent application on behalf of Materia Inc. W02008 / 08440. In particular, the catalysts described in WO2008 / 046106, from page 15 paragraph [0061] to page 35 paragraph [106], and those described in WO2008 / 08440, from page 20 paragraph [0068, can be used ] to page 39 paragraph [0020].

Other metathesis catalysts that can be used in the present invention are, for example, those described in international patent application WO2009 / 020667 on behalf of Elevance Renewable Science Inc., from page 18 paragraph [0067] to page 46 paragraph [0120].

Other patent applications describing metathesis reactions, again on behalf of Elevance Renewable Science Inc., are international patent application WO2010 / 062958, which describes a metathesis reaction followed by a hydrogenation of hydrocarbon cuts to C16, for obtaining aviation fuel, and patent application WO2011 / 046872 describing the hydrogenation of the olefinic cut from a metathesis reaction to obtain biofuels such as diesel, naphtha and aviation fuel.

US patent application US20120255222, again on behalf of Elevance Renewable Science Inc., claims the production of additives to improve the cold flow properties of fuels by a metathesis stage. These additives can in fact be added to diesel to improve their properties.

In the present invention, the separation step (b) can be carried out by distillation.

The hydrodeoxygenation process of step (d) is preferably carried out with hydrogen in the presence of a hydrodeoxygenation catalyst; and / or the hydroisomerization process of phase (d) is carried out with hydrogen in the presence of a hydroisomerization catalyst.

The hydrodeoxygenation and hydroisomerization processes performed in the present invention and the hydrodeoxygenation and hydroisomerization catalysts used are, for example, those described in the applications

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of patents WO2008 / 058664, EP1728844, WO2009 / 039347, WO2009 / 039335, WO2009039333, WO2009 / 158268 and in the American patent application US2009 / 0077865, where all these patent documents are in the name of ENI S.p.A. and UOP 11c.

In particular, in accordance with what is described in patent application WO2008 / 058664 on page 7, line 24 to page 9, line 24, all hydrogenation catalysts known in the art comprising at least one metal selected from metals of group VIII or group VIB, suitably supported, can be used as hydrodeoxygenation catalysts. Suitable supports are, for example, one or more metal oxides, preferably selected from: alumina, silica, zirconia, titanium oxide or mixtures thereof. Suitable metals are preferably Pd, Pt or Ni or Ni-Mo, Ni-W, Co-Mo or Co-W couples.

Some hydroisomerization catalysts that can be used in the present invention are illustrated from page 13, line 19 to page 24, line 21 of WO2008058664.

The transesterification reaction carried out in step c) with an alcohol selected from methanol, ethanol or mixtures thereof, in order to obtain a mixture of methyl and / or ethyl esters and glycerol, is carried out according to any of the methods known in the art. In this case, the subsequent separation of glycerol and saturated and unsaturated esters is carried out according to any of the methods known in the art, for example, by distillation.

Brief description of the figures

Figure 1: the steps of the process of the invention according to a preferred embodiment are illustrated in a block scheme (scheme 1): the metathesis step is carried out, followed by separation of olefins with less than 18 carbon atoms, hydrolysis of the fraction comprising triglycerides by the addition of C1-C2 alcohols, separation of the glycerin produced and the unsaturated and saturated esters formed, where only the last fraction is initiated to the Ecofining process for the formation of green diesel fuel Aviation and gasoline.

Figure 2: the steps of another procedure not according to the invention are illustrated in a block scheme (scheme 2): the metathesis step is carried out, followed by separation of olefins with less than 18 carbon atoms, Ecofining procedure for the formation of green diesel, naphtha and aviation fuel.

Detailed description of the figures

Figure 1

As indicated in the scheme of Figure 1, in a preferred embodiment of the process of the invention, the metathesis reaction can be carried out in the triglyceride mixture that forms the starting oil with C2-C6 olefins, preferably C2- C4 Olefins having a number of carbon atoms lower than C18 (i.e., C6-C-ia), formed after the metathesis reaction, which can be used as intermediates for the production of detergents, additives, lubricants and / or plastic materials or components that can be used in the field of oil exploration and production, are easily separated by distillation from the rest of the reaction mixture which, after separation, is still composed of triglycerides of saturated fatty acids and fatty acids unsaturates that are formed as a result of the metathesis reaction. The latter are characterized in that they have an unsaturated hydrocarbon chain having a length that is less than the starting length. A transesterification reaction is then carried out in these triglycerides, thus obtaining unsaturated esters of medium chain acids (for example, C10 if the metathesis has been performed with ethylene or 9-decenenoic acid ester, C10-C13 if, on the other In part, the metathesis has been performed with 1-butene, etc.) and saturated fatty acid esters, mainly C16 and C18, initially present in the oil and which have remained unchanged through the metathesis reaction. Again, the difference in boiling points allows easy separation of unsaturated esters from saturated esters. The latter are sent to the hydrotreatment procedure, or to the Ecofining procedure described above as a two-stage procedure, where the first stage consists of a hydrogenation / deoxygenation reaction (hydrodeoxygenation), while the second stage is a hydroisomerization stage. / cracking.

The treatment of a composition of C16 and C18 methyl esters with respect to the treatment of lipids or glycerides (i.e., glycerin esters) minimizes unwanted propane formation (mainly derived from the direct hydrogenation of glycerin), obtaining a further distribution Narrow of products with greater application advantages.

The output of the metathesis section actually becomes richer in the saturated C16 component. However, the typical characteristics of the second stage of Ecofining (hydroisomerization, cracking) widens the variety of products that lead to the formation of aviation fuel (predominant), naphtha and diesel that has better engine performance.

Figure 2

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Similarly to what has been described for Figure 1, in a process that is not according to the invention, the metathesis reaction can be carried out in the triglyceride mixture that forms the starting oil with C2-C6 olefins, preferably C2-C4. Olefins having a number of carbon atoms lower than C18 (i.e., C6-C18), formed after the metathesis reaction, which can be used as intermediate compounds for the production of detergents, additives, lubricants and / or materials or plastic components that can be used in the field of oil exploration and production, are easily separated by distillation from the rest of the reaction mixture which, after separation, is still composed of triglycerides of saturated and unsaturated fatty acids that are formed as a result of the metathesis reaction. The latter are characterized in that they have an unsaturated hydrocarbon chain having a length that is less than the starting length.

This mixture can be sent directly to the hydrocracking or to the Ecofining procedure described above as a two-stage process, wherein the first stage consists of a hydrogenation / deoxygenation (hydrodeoxygenation) reaction, while the second stage is a hydroisomerization / cracking that, due to the presence of acids that have a C10-C13 chain, again produce not only a diesel cut but also naphtha and aviation fuel.

In view of what has been described above, the process of the present invention has the following advantages:

- a complete enrichment of the starting renewable biomass, with a specific production of renewable products for use in the field of both intermediate products and fine chemicals, and also in refining;

- lower costs (OPEX - operating expenses) in the Ecofining section, thanks to a reduction in hydrogen consumption due to a decrease / absence of unsaturations in the chain of esters sent to said procedure;

- improvement in the same section of hydrotreatment (Ecofining) since the raw material is already previously treated and purified in the metathesis section, with the consequent reduction in investments (CAPEX - capital expenditures) and OpEX;

- lower propane production in the Ecofining section due to the absence of glycerin derivatives in the raw material;

- Maximization of the variety of products to use in the field of biofuels since they are useful component products in the field of gasoline, aviation fuel and diesel.

Hereinafter some examples of embodiments of the present invention are provided for illustrative, but not limiting purposes.

Examples

Example 1 (according to the scheme in Figure 1)

1 ton of palm oil, consisting of approximately 49% myristic, palmitic and stearic derivatives (saturated components) and 41% oleic acid, 10% linoleic acid, is sent to a metathesis section with excess ethylene at a 10 bar pressure (stoichiometric consumption of 41 kg of ethylene). The reaction is carried out at 60 ° C for approximately 1-1.5 hours in the presence of 100 ppm of ruthenium-based metathesis catalyst. After separating the catalyst, the reaction mixture is distilled according to known techniques, in order to separate approximately 200 kg of 1-decene and 32 kg of 1-heptene. The lower mixture is sent to a hydrolysis section with methanol (60 ° C, approximately 2 hours of residence time, 1% NaOMe catalyst in MeOH) obtaining approximately 108 kg of glycerin, 330 kg of methyl ester of acid 9 - Decenoic acid, and approximately 470 kg of C16-C18 saturated acid methyl esters (85% C16 ester). The 470 kg of saturated esters are distilled off and sent to an Ecofining section, obtaining approximately 375 kg of components suitable for use in the field of aviation, diesel and naphtha fuel biofuels. The components 1-Decene, 1-Heptene and Methyl Ester of 9-Decenoic Acid are used in the field of the production of biochemicals (intermediate products that can be used for the production of detergents, additives, lubricants and / or materials or plastic components that can be used in the field of oil exploration and production).

Claims (16)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. Process for producing olefinic compounds and a hydrocarbon fuel or a fraction thereof, comprising: (a) metastasize a mixture of glycerides having at least one unsaturated hydrocarbon chain, possibly mixed with free fatty acids, with at least one C2-C6 monoolefin, in the presence of a metathesis catalyst, in order to obtain a mixture of glycerides having at least one unsaturated hydrocarbon chain with a length less than the initial one, and a mixture of C6-C18 olefins; (b) separating the C6-C18 olefin mixture from the glyceride mixture obtained in step (a); (c) subjecting the glyceride mixture obtained in step (b) to a transesterification reaction with an alcohol selected from methanol, ethanol or mixtures thereof, in order to obtain a mixture of methyl and / or ethyl esters and glycerol; (c ') separate the glycerol from the mixture of methyl and / or ethyl esters, and then (c ") separating the methyl and / or ethyl esters having an unsaturated hydrocarbon chain from the methyl and / or ethyl esters having a saturated hydrocarbon chain, (d) subject the methyl and / or ethyl esters having a saturated hydrocarbon chain obtained in step (c ") to a catalytic hydroxy oxygenation process and then catalytic hydroisomerization, in order to obtain the hydrocarbon fuel or a fraction thereof. 2. The method according to claim 1, wherein the hydrocarbon fuel is selected from: diesel, naphtha, aviation fuel, or mixtures thereof. 3. Method according to any one of the preceding claims, wherein the mixture of C6-C18 olefins obtained from step (b) and / or the methyl and / or ethyl esters having an unsaturated hydrocarbon chain obtained in step (c ") are intermediate products that can be used for the preparation of detergents, additives, lubricants and / or plastic materials or components that can be used in the field of oil exploration and production. 4. Process according to any one of the preceding claims, wherein the glycerides having at least one unsaturated hydrocarbon chain used in the mixture of step (a) are glycerides, preferably triglycerides, of plant or animal origin or of microbial origin. 5. The method according to claim 4, wherein the glycerides of vegetable or animal origin or of microbial origin are glycerides of fatty acids having at least one C12-C24 hydrocarbon chain, mono or polyunsaturated. Method according to claim 4, wherein the glycerides are selected from: vegetable oils, such as: sunflower, rapeseed, canola, palm, soy, hemp, olive, flaxseed, mustard, peanut, castor, coconut and resin; oils and / or recycled fats from the food industry; lipids from seaweed; animal oils or fats, such as: lard, cream of lard, tallow, dairy fats; or mixtures thereof. 7. The method according to any one of the preceding claims, wherein said at least one C2-C6 monoolefin, preferably C2-C4, is selected from: ethylene, propene, 1-butene, but-2-ene, 2-methyl-propene , or mixtures thereof. 8. The method according to any one of the preceding claims, wherein in step (a) the molar relationship between the double bonds of the glyceride mixture having at least one unsaturated hydrocarbon chain and the double bonds of said at least one C2 olefin -C6, is between 1: 0.1 and 1:20. 9. Method according to any one of the preceding claims, wherein step (a) is carried out at a temperature of 20 to 120 ° C, for a period of time in the range of 0.5 to 6 hours, preferably of 20 to 80 ° C and 0.5 to 3 hours. Method according to any one of the preceding claims, wherein step (a) is carried out at a pressure of between 1 and 30 bar, preferably between 1 and 15 bar. 11. The method according to any one of the preceding claims, wherein the metathesis catalyst of step (a) is a carbine complex of a transition metal of group 8, in particular selected from: ruthenium, molybdenum, osmium, chromium, rhenium, tungsten. 12. Method according to any one of the preceding claims, wherein the separation step (b) is carried out by distillation. 13. The method according to any one of the preceding claims, wherein the hydrodeoxygenation process of step (d) is carried out with hydrogen in the presence of a hydrodeoxygenation catalyst. 14. A method according to claim 13, wherein the hydrodeoxygenation catalyst comprises at least 5 a metal selected from the metals of group VIII or group VIB, preferably Pd, Pt or Ni or Ni-Mo, Ni- couples. W, Co-Mo or Co-W. 15. A process according to claim 13, wherein the hydrodeoxygenation catalyst is supported on at least one metal oxide, preferably selected from: aluminum, silica, zirconia, titanium oxide or mixtures thereof. Method 16. according to any one of the preceding claims, wherein the method of Hydroisomerization of step (d) is carried out with hydrogen in the presence of a hydroisomerization catalyst. 17. The method of claim 16, wherein the hydroisomerization catalyst comprises at least one metal of group VIII, preferably selected from: Pt, Pd, Ni and Co, possibly in admixture with at least one metal of group VIB, preferably selected of: Mo and W, and an acid type support.